Die for forming can ends.



(No Model.)

w/TNESSES J. M. K. LETSON.

DIE F (Application led Sept. 19, 1898.)

Patented July 25', |899.

0R FOBMING CAN ENDS.

i UNITED STATES l PATENT OEEICE.-

JAMES MOORE K.. LETSON, OF VANCOUVER, CAADA.

D|E`FOR FORMING CAN ENDS.

SPECIFICATION forming part of Letters Patent No. 629,575, dated J' uly 25, 1899. Application filed September 12, 1898. Serial No. 690,794. (No modelJ.

T0 tZZ whom it may concern/f Be it known that I, JAMES MOORE K. LET- sON, a citizen of the Dominion of Canada, residing in the city of Vancouver, in the Province of British Columbia, Canada, have invented a new and useful Die for Forming CanEnds, of which the following is a speciiication.

My invention relates to improvements in dies forming the cover or bottom of cans, in which I employ a detachable center for the base of the die; and my object is to provide a die that although similar in form and construction to the ordinary ones in use by reason of the center piece being removable it may be changed or when this part becomes worn or dulled another center may be substituted without, as heretofore, the necessity of re-turnin g or supplying a new base for Y the die.

I attain my object by the mechanism illustrated in the accompanying drawings, in which- Figure 1 is a plan of my improved die without the punch, and Fig. 2 is a sectional elevation taken on the line o o. This figure shows the punch above the base of the die.

Similar letters and figures refer to similar parts throughout both views.

The base of the die 10 is formed, as in the usual way, with the upwardly-projecting portion 10 and the depending ring or hub 10b. The portion 10a at its center is provided with a recess 1l, the walls of which are slightly flared outwardly. A removable center piece 12 is arranged in the recess 1l and hasv its lower portion reduced and tapered to I it the said recess and the taperedwalls thereof, and its outer vertical edge is flush with the outer walls of the upper portion of the base. This center piece 12 is the essential feature of my invention, and it is rigidly fastened to the upwardly-projecting part of the base 10 by the screws 13, or it may be fastened by any other convenient means, so that when the edges become worn the same may be replaced by a new one, thus avoiding the necessity of renewing the base of the die..

Arranged quadrally in the base, within recesses placed in the outer walls of the upwardly-projecting portion 10, and -passing intothe depending hub 10b are spiral springs 14, housed Within the base and engaging the lower face of the center piece and projecting beyond the periphery of the same, the upward movement of the springs being limited by the center piece. These springs l14 when the center 12 is brought close to its seat by the screws 13 are exerting an upward pressure, and 15 indicates an annular ring which lies upon the outer sides of the springs 14. At the lower outer periphery of the ring 15 is a flange 15u. of the ring 15, above the flange 15a, is a large cutting-ring 16, this being secured to the base 10 by screws 17.

The ring 16 has its upper surface formed with an annular cutting edge 16a, which is disposed at the'base of the beveled edge of the ring 15. By thus arrangingthe edge 16a and the ring 15 the punching and cutting actions at the beginning ofthe engagement of the punch with the can end will not be s imultaneous. Therefore the strain on the operating parts will not beso great as if the surface of the ring 15 and the cutting edge 16a were in the same plane. Beneath the ringl there is sufficient annular space, as 18, to allow of the said ring being driven downward when the punch o, makes a stroke, and by reason of the lower annular rim of the punch being beveled inwardly and the upper rim of the ring 15 being beveled out*- wardly at the same pitch when such punch is forced down the sheet metal to be formed into covers will be pressed between the bev els, and as the punch passes tothe full stroke the cover will be formed over the center 12 and its edges will be withdrawn from between the beveled surfaces and forced into a vertical annular position to fit the size of can for which itwas intended. f

When the punch o is forced down, as afore said, the knockout block 19 will force the springs 2O backward and will lie in the recess 2l in the inner cavity of the punch until all of such recess is occupied thereby, and the lower surface of said knockout will impinge the cover on the center piece 12, and thus the said cover or can end will be given the proper form.

The engaging surfaces of the knockout Embracing the outer sides IOO their planes designed to block 19 and the center piece l2 may have give the covers any pattern desired.

When the puneh is raised or extracted from the cutting-ring 16, it carries the can end with it; but as the knockout block is relieved of pressure by being raised from lthe center piece l2 the springs 2O Will foreeit down to its normal position and free the said can end.

Passing through the pu neh a and the knockout block is a piercer 22. This may be set so that an aperture of the desired size will he made in the cover when it is pressed down by the action of the plunger.

It is shown that my invention is very simple, but at the same time provides a means Whereby the removal of the base of the die is avoided. It is therefore obvious that my invention is of vital importance to any canzo making or canning establishment.

Having 110W described my invention, what I elaim ism In a die for forming the ends of cans, the combination of a base, the outer cutting-ring rigid with the hase and having an upper cutting edge, a detachable center piece rigidly mounted upon the base, the vertical springs, housed in the base and engaging the lower face of the eenter pieee and having their upward movement limited by the same, said springs projecting beyond the periphery of the center piece,a depressible ring located between the center piece and the cutting-ring and supported upon the said springs, and a punch, substantially as described.

JAMES MASON. W. G. TRETHEWEY. 

